Several species of hibiscus have been used for medical purposes. Hibiscus rosa-sinensis has been used in ancient Indian medicine, Hibiscus sabdariffa has been used as a folk medicine in Canada for high blood pressure, and Hibiscus cannabinus has been studied for head lice, although more evidence is needed.

Hibiscus sabdariffa and the compounds that it contains are likely to be studied more in the future. There is limited safety data on hibiscus, although it is popularly used as a tea. Research reports that it is well-tolerated when taken by mouth.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Extracts of hibiscus have been found to lower blood pressure. More high-quality studies are needed to confirm these results, although the use of hibiscus for lowering blood pressure looks promising.

B

Early research suggests that Hibiscus sabdariffa extract may have antioxidant benefits. However, higher quality studies are needed before firm conclusions may be made.

C

The effects of hibiscus on cholesterol levels have been mixed. More high-quality research is needed before a conclusion may be made.

C

A combination therapy containing hibiscus has been used for lice. However, the effects of hibiscus alone are unclear. Further study is needed.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

As an antioxidant, 10 grams of powdered H. sabdariffa L. extract (HSE) dissolved in 200 milliliters of tap water has been taken by mouth as a single dose immediately before drinking.

For high cholesterol, 100 milligrams of H. sabdariffa extract or extract powder has been taken by mouth daily for 4-12 weeks. Two capsules of 500 milligrams Hibiscus sabdariffa extract each has been taken by mouth daily for 90 days. Sour tea sachets, each containing 2 grams of Hibiscus sabdariffa, have been used twice daily for one month.

For high blood pressure, 10 grams of dry calyx from Hibiscus sabdariffa infused with 0.5 liters of water has been taken by mouth daily before breakfast for four weeks. A dose of 150 grams of sour tea has been taken by mouth at least one hour before measuring blood pressure for 12 days. A dose of 240 milliliters of tea containing 1.25-2 grams of H. sabdariffa (steeped over 6-30 minutes in boiling water) has been taken by mouth 1-3 times daily for 4-6 weeks. Tea prepared with hibiscus powder containing 250 milligrams of anthocyanins (a compound found in hibiscus) has been taken by mouth daily for four weeks. Two spoonfuls of blended hibiscus tea has been added to one glass of boiled water (steeped for 20-30 minutes) and taken by mouth once daily for 15 days.

Children (under 18 years old)

There is no proven safe or effective dose for hibiscus in children.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people with known allergy or sensitivity to hibiscus, its parts, or members of the Malvaceae family.

Side Effects and Warnings

Hibiscus is possibly safe when taken by mouth in the form of Hibiscus sabdariffa (9.6 milligrams of anthocyanins) to treat high blood pressure for up to four weeks.

Hibiscus may cause low blood pressure. Caution is advised in people who have high or low blood pressure, or those taking drugs or herbs and supplements that lower blood pressure.

Hibiscus may lower blood sugar levels. Caution is advised in people with diabetes or low blood sugar, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Use cautiously in people who have high cholesterol, nervous system disorders, and stomach or intestine disorders, or those taking cholesterol-lowering agents.

Use cautiously in pregnant or breastfeeding women, due to a lack of evidence.

Avoid in people with known allergy or sensitivity to hibiscus, its parts, or members of the Malvaceae family.

Pregnancy and Breastfeeding

There is a lack of scientific evidence on the use of hibiscus during pregnancy or breastfeeding. Use cautiously in pregnant and breastfeeding women.

Hibiscus may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Hibiscus may also interact with agents for cancer, agents for the ears, agents for the heart, agents for the immune system, agents for the kidneys, agents for malaria, agents for the nervous system, agents for the stomach and intestines, agents for the urinary tract, agents that increase sun sensitivity, antibiotics, anti-inflammatory agents, antiviral agents, chloroquine, cholesterol-lowering agents, fertility agents, hormonal agents, and hydrochlorothiazide.

Interactions with Herbs and Dietary Supplements

Hibiscus may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Hibiscus may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.

Hibiscus may also interact with antibacterial herbs and supplements, anti-inflammatory herbs and supplements, antioxidants, antiviral herbs and supplements, cholesterol-lowering herbs and supplements, fertility herbs and supplements, herbs and supplements eliminated by the kidneys, herbs and supplements for cancer, herbs and supplements for the heart, herbs and supplements for the immune system, herbs and supplements for malaria, herbs and supplements for the nervous system, herbs and supplements for the stomach and intestines, herbs and supplements that increase sun sensitivity, hormonal herbs and supplements, and kava.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.